1. Field of the Invention
The present invention relates to a pigment ink for ink jet recording systems, especially suitable for the thermal type ink jet recording system, which will provide ink discharge stability and durability to the recording head. The present invention also relates to an ink cartridge, recording unit, an ink jet recording method using them, an ink jet recording apparatus and a method for stabilizing the ink discharge.
2. Related Background Art
The ink jet recording method is a method of recording by applying energy to ink to eject an ink droplet from a nozzle to deposit the ink onto a recording medium such as paper.
Recently the size of an ink droplet discharged from a single nozzle has become smaller and smaller in order to meet the need for an ink jet recorded image of extremely high quality comparable to that of silver halide photography, and now ink jet printers that eject an ink droplet of not larger than about 10 pl (picoliter) are commercially available. Also with increasing demand for higher printing speed, it is necessary to accommodate a higher drive frequency (for example 5 kHz or higher, preferably 10 kHz or higher).